1. Field of the Invention
This invention relates to electrical connectors. More particularly, it relates to electrical connectors specially adapted for subsea use.
2. Description of the Related Art including information disclosed under 37 CFR 1.97 and 1.98
In the subsea environment, providing an electrical penetration—a power or signal connection through the wall of a vessel or housing—presents a number of difficulties. Water pressure increases with depth. For example, at a 12,000-ft water depth, subsea equipment is subjected to a pressure of 5350 psi from the water column. Since the interior of a vessel, pod or housing will often be maintained at atmospheric pressure (to facilitate assembly and service at the surface), a substantial pressure differential typically exists across an electrical penetrator installed in the vessel wall when the device is deployed in the ocean. Seawater will move under the influence of the pressure differential into the vessel through any leak pathway in the penetrator.
One representative example of subsea electrical penetrator application is an underwater electrical cable on the seafloor which connects to a pod containing one or more sensors—e.g., a hydrophone. Power to the sensors and signals from the sensors must pass through the wall of the pod in order to connect with the subsea cable. An electrical penetrator provides a watertight, electrically insulated connection through the exterior wall of the pod.
One example of a subsea electrical penetrator of the prior art is shown in FIG. 1. Penetrator 10 is shown installed in wall 12 of an undersea pod, housing or similar vessel. Penetrator 10 comprises generally cylindrical body 14 having a central axial bore 13. Cylindrical projection 15, which is coaxial with bore 13, extends from face 28 of body 14. Connector pin 16 passes through bore 13 and projection 15 generally on the axis of each and spaced apart from the interior walls of bore 13 and projection 15. Connector pin 16 is an electrical conductor which may be adapted for solder-type, crimp-type or other such electrical connections at one or both ends. Glass seal 20 surrounds connector pin 16, mechanically connecting it to penetrator body 14 while providing electrical insulation from penetrator body 14. Outer insulator 22 substantially fills the annular space between pin 16 and the inner wall of projection 15. Insulator 22 typically comprises a thermoplastic or thermoset dielectric material.
Conductor 19 of cable 18 (which may be an undersea cable) is electrically connected to pin 16 at external connector 24. The opposing end of pin 16 has internal connector 26 for connecting to a conductor within the pod, housing or vessel in which penetrator 10 is installed.
Boot seal 30 surrounds that portion of connector pin 16 which extends beyond penetrator body 14. Boot seal 30 is typically fabricated from natural or synthetic rubber such as Neoprene or polychloroprene. Boot seal 30 of prior art penetrator 10 is comprised of outer section 32, which engages jacket 17 of cable 18, middle section 34, which seals to the outer surface of connector pin 16, and inner section 36 which engages the outer wall of projection 15. Ideally, each of these engagements provides a watertight seal.
It has been found, in practice, that the mechanical seals of a penetrator 10 do not always provide a watertight seal over time in deep water. Leakage around connector pin 16 and into cable 18 may occur. The present invention provides an improved watertight seal between both the cable and the penetrator and between the penetrator and the vessel, housing or pod on which it is installed.